High voltage terminal block



1966 F. R SULLIVAN 3,266,007

HIGH VOLTAGE TERMINAL BLOCK Filed May 18, 1964 IN VENTOI? FREDERICK 72.SUZL/V/M United States Patent 3,266,007 HIGH VOLTAGE TERMINAL BLOCKFrederick R. Sullivan, Auburn, N.H., assiguor to Sanders Associates,Inc, Nashua, Nl-L, a corporation of Delaware Filed May 18, 1964, Ser.No. 368,102 9 (Jlaims. (Cl. 339-128) to guard against the above notedproblems was to pot the entire terminal area with some suitable pottingcompound. While this provided the needed protection against arcing andcorona effects, these potted terminals presented numerous deficienciesin that they required the complete destruction of the terminal area inorder that the electrical leads connected therein be removed forpurposes of repair or testing. The need for special solvents to dissolvethe potting compound also presented another problem.

There have been in the prior art attempts to solve this problem. Anumber of contributions typical of one effort is the high voltageconnector to DeTar, Patent No. 2,897,-

471, which makes provision to assure arc-free operation at higheraltitudes. The DeTar patent, While providing one approach to a solutionof the problem, does not present an electrical connection which istotally free of the problems noted above, the DeTar patent being complexin a number of elements and .the need for a multitude of C rings toprovide adequate sealing of the units connected.

A patent to Stevens, No. 2,677,115, represents another prior artapproach, but this patent also presents an electrical connection whichdoes not have the isolation which will be present in the invention to bedescribed hereafter.

Important to the invention to be described is the recognition that theremust be, from the point of electrical interconnection between leadssought to be connected, a minimum length of mating connector interfaceneeded to ultimately assure the electrical connection from havingpresent therein sufiicient air dielectric within the mating portion ofthe connector which might allow the ionization thereof and .aconcomitant breakdown of this air dielectric with related arcing andcorona deficiencies.

The invention noted above avoids all of the problems present in theprior art and does so with a minimum of parts but with a maximum ofelectrical isolation and does so in the minimum of space with aversatility of electrical lead wire input and output heretofore notpresent in the prior art.

It is therefore an object of this invention to provide a high voltageterminal that has no high altitude arcing and corona effects and isreadily demountable.

Another object of this invention is to provide a high voltage terminalblock that can support a plurality of electrical leads of varyingoutside dimensions.

Another object of this invention is to provide a high voltage terminalblock that can have a plurality of electrical leads entering and leavingthe block at dilferent angles.

Another object of this invention is the provision of a high voltageterminal block that is free from air contamination at the point ofelectrical interconnection.

Another object of this invention is to provide a high voltage terminalblock that may be readily assembled or Patented August 9, 1966disassembled without damage to any portion of the terminal blockarrangement.

Another object of this invention resides in the provision of a highvoltage terminal connector that avoids air contamination by utilizing aninterference fit socket arrangement that resists inadvertent separationbut is readily interconnected.

Other and further objects of this invention Will be apparent from thefollowing description of preferred embodiments thereof takeninconnection with the accompanying drawing.

In the accompanying drawing:

FIG. 1 is a three dimensional illustration depicting several aspects ofone embodiment of the invention;

FIG. 2 is a cross sectional view of a second embodiment of theinvention; and

FIG. 3 is another configuration of the invention embodied in FIG. 2.

Reference is now made to FIG. 1 in which there is illustrated oneembodiment of the subject invention. The high voltage terminalarrangement is made up of a high voltage terminal block 11 which hasformed therein a number of slotted openings or channels 12 and 13.Mounted in the center of these channels are terminal posts .14, 16 and17, each of the terminal posts having therein threaded openings 18 and19 on the upper surface. These terminal posts 14, 1'6 and 17 may be ofan insulating material of the same composition of the high voltageterminal block 11. Bakelite is one such commercially available materialthat is suitable for a high voltage terminal block arrangement of thetype depicted herein. When very high strength is needed, the block 11may be made of metal such as brass or steel and the terminal posts areconstructed of an insulating material.

In this particular embodiment the terminal post 17 is of a conductivematerial which passes downwardly through the terminal block 11 for asubsequent electrical interconnection to an electrical lead wire 38which is connected to the post in a manner not shown. In order that theelectrical connection of the lead wire 38 be [free from arcing thebottom of the block 1J1, it would require the presence of a pressurizedhousing (not shown) secured to the block 11.

At the central area of the slotted openings of channels 12 and 13 arearcute central regions 21 and 22 which are to receive a lower preformedresilient insert 23 and an upper preformed resilient insert 24. Theseresilient inserts may be fabricated from a number of materials, two ofwhich are rubber or a silicone type rubber which are easily formed ormolded and provide the resilient surrounding medium in which electricallead wires 28 and 29 will ultimately reside when the entire device isassembled. Each of the preformed resilient inserts 23 and 24 have in thefaces thereof electrical lead grooves 2 6 and 27. The radii of theseelectrical lead grooves are determined by the size of the outsidediameter of the electrical lead wire being used and in those situationsin which the wire is very small, the grooves in turn are' molded of asmaller radii to complement the wire to be handled.

Depicted in FIG. 1 directly above the slotted opening or channel 12there is shown in an exploded perspective the preformed resilientinserts 23 and 24 and in between these two inserts are the electricallead wires 28 and 29 having their electrical lead eyelets 31 and 32 inregister with a terminal post opening 25 in the lower resilient insert23.

A screw 33, when the device is assembled, passes through the eyelets 31and 32 and then through the terminal post opening 25 into the threadedopening 18 of the terminal post 14. Once the lower performed resilientinsert 23 is placed down with the channel 12 and the electricalconnection as described above has been made, the lower insert 23 may becoated with a silicone lubricant prior to the placing of the upperpreformed resilient insert 24 down upon the lower insert 23. When thisupper insert 24 has been placed in position, it is then placed underpressure by a top plate 51 which is held in place by screws 52, 53, 54and 56 and in so being held in place, the pressure exerted upon theupper preformed resilient insert is suflicie-nt to cause the siliconelubricant, described above but not shown in the drawing, to be forcedoutwardly along the grooves 26 and 27 and the wires 28 and 29. The abovearrangement along with any air trapped therein establish the ultimate ina high voltage, high altitude terminal junction which is capable ofresisting the corona and arcing effects inherently present in terminalblocks exposed to altitudes in excess of 50,000 feet and voltages in amagnitude of -20,000 volts.

As can be seen, the terminal block 11 is susceptible of a number ofvariable arrangements; that is to say, the

slotted opening 13 may have a portion thereof extending at an angle awayfro-m the terminal post 16 thereby permitting two wires to beinterconnected so that they are joined at an angle that is less than180. The resilient inserts 23 and 24 which fit in slotted opening 12illustrate electrical lead interconnection in the 180 position.

To the right of the slotted opening or channel 12, there is anotherexample of how two parallel electric lead wires may enter the highvoltage block 11 between two resilient inserts 30 and 4 1 and form anelectrical connection at screw 37 which in turn is connected toelectrical lead wire 38 which provides a three-way junction in anisolated region of the terminal block 11.

In position to the far left of FIG. 1 is shown an electrical lead wire10 in an assembled condition with preformed inserts 39 and 40 in matingrelationship.

Reference is now made to FIGS. 2 and 3 where similar numerals depictsimilar elements in the two embodiments set forth in these figures.

Referring specifically now to FIG. 2 there is shown a female preformedelement 61 which may be cast of a rigid insulating material ofsufiicient dielectric strength to meet the high voltage needs to beexperienced by the electrical interconnection to be described more fullyhereafter. The female preformed element 61 has an opening 62 at one end.At the base of the preformed element 61 there is molded therein ashouldered contact member 63 which has a contact prong 64 which willmate ultimately with a slotted portion 74 to be described hereafter.

Securely soldered within the preformed element 61 is an electrical leadwire 66. The opening 62 has a truncated tapered contour 67 which hastherein concave impressions 6S and 69. The contour of the opening isimportant to the invention for it has been discovered that when highaltitude operations are coupled with high voltages, there is a need fora maximizing of the total interface distance from, for example, contactprong 64 and the exterior of the opening 62. The presence of only onesuch contour or impression such as 69 would be insufficient to meet theneeds of high voltage operations.

Directly above the opening 62 there is depicted a mating male element71. It is imperative to the successful operation of this invention thatone of the elements 61 or 71 must be of a resilient material. In theillustration convered by FIG. 2, the mating male element 71 is of such aresilient material. Rubber or silicone rubber are adequate materials tomeet the needs of high voltage operations. The use of silicone grease atthe interface also enhances the reliability of this arrangement.

Secured within the male element 71 is a shouldered element 73. Thisshouldered element 73 has a slotted portion 74, the slotted portion '74having a bore opening therein, the diameter of which is slightly smallerthan the outside diameter of the contact prong 64 thereby permitting themale element 71, when fitted within the preformed element 61, to expandslightly to form an interference fit with the prong 64. Accordingly,this invention contemplates the possible usage of a resilient materialfor the female element 61 and a rigid material for the male element 71.Of course, this would require that the slotted portion 74 and shoulderedelement 73 be located within the element 61 because it is essential thatthe slotted portion 74 be mounted within a resilient material that willafford the needed expansion to provide the interference fit noted above.

Reference is now made to FIG. 3 in which there is shown a secondembodiment of the invention illustrated in FIG. 2. This embodiment showsa right angle connection of electrical lead wires 66 and 72. Thisillustration is also highly illustrative of one important aspect of thisinvention in that it shows the mating imaile element 71 fitted inposition and also shows an interface 75. As can be appreciated in thisfigure, the distance from the electrical contact prong 64 along theinterface 75 is maximized by the presence of the concave impressions 68and 69 along which any air that might be trapped would be located. Forit is the ionization of air along the interface of most electricalconnections that provides the undesirable arcing and corona eifects. Itcan be seen that this arrangement provides a maximum of surfaceinterface while providing a secured electrical connection enhanced bythe convoluted surface of the mating elements 71 and 61.

While there has been hereinbefore described what are at presentconsidered preferred embodiments of the invention, it will be apparentthat many and various changes and modifications may be made with respectto the embodiment illustrated, without departing from the spirit of theinvention. It will be understood that all changes and modifications asfall fairly within the scope of the present invention, as defined in theappended claims, are to be considered as part of the present invention.

What is claimed is:

1. A high voltage terminal block capable of high altituide usage withoutarcing or corona disabilities comprised of:

(A) a terminal body having at least one transverse channel therelacross,

(B) a terminal post disposed in said channel to carry a set ofelectrical high voltage lead wires,

(C) fastening means to secure said electrical leads to said tenmintalpost,

(D) a plurality of shaped resilient preformed inserts mounted in matingrelationship in said channel,

(E) a first one of said shaped resilient inserts mounted beneath saidelectrical leads and extending along the bottom of said channel,

(F) a second resilient preformed insert mounted above .and in matingcontact with said electrical leads and said preformed insert to therebytotally encapsulate said electrical leads and said terminal post and prevent the possibility of possible high voltage arcing and corona effectsto adjacent objects, and

(G) a top plate securely mounted on said terminal body and in contactwith said second preformed insert to thereby assure the electricalintegrity of said electrical lead wires. 7

2. The combination set forth in claim 1 wherein said top plate and saidsecond prefonmed insert are readily removable to thereby facilitate theinspection and removal of said electrical leads without removing thehigh voltage terminal block capability to be reused again.

3. The combination set forth in claim 1 wherein there is an electricallyinert substance between said firs-t and said second resilient preformedinserts.

4. The combination set forth in claim 3 wherein said substance is alubricant.

5. The combination set forth in claim 1 wherein said channel has a paththat has an angled position starting at said terminal post to therebypermit said electrical leaid Wires to be joined at .some predeterminedangle.

6. The combination set forth in claim 1 wherein said channel terminatesat a point just past said terminal post and said electrical lead wiresare mounted in a parallel arrangement to said post.

7. The combination set forth in claim 1 wherein said tenminal post iselectrically conductive and passes downwardly through said terminalblocks body to thereby provide an externally located terminal forelectrical connection to another component.

8. The combination set forth in claim 1 wherein said terminal body ismade of a plastic insulating material.

9. The combination set forth in claim 1 wherein said terminal body ismade of a high strength metal.

References Cited by the Examiner UNITED STATES PATENTS 2,275,762 3/1942Horton 339-60 2,766,436 10/1956 Luebking 339-498 2,907,973 10/ 1959Stevens 33959 2,924,808 2/1960 Hewes et a1 339-198 PATRICK A. CLIFFORD,Primary Examiner. J. H. MCGLYNN, Assistant Examiner.

1. A HIGH VOLTAGE TERMINAL BLOCK CAPABLE OF HIGH ALTITUDE USAGE WITHOUTARCING OR CORONA DISABILITIES COMPRISED OF: (A) A TERMINAL BODY HAVINGAT LEAST ONE TRANSVERSE CHANNEL THEREACROSS, (B) A TERMINAL POSTDISPOSED IN SAID CHANNEL TO CARRY A SET OF ELECTRICAL HIGH VOLTAGE LEADWIRES. (C) FASTENING MEANS TO SECURE SAID ELECTRICAL LEADS TO SAIDTERMINAL POST, (D) A PLURALITY OF SHAPED RESILIENT PREFORMED INSERTSMOUNTED IN MATING RELATIONSHIP IN SAID CHANNEL, (E) A FIRST ONE OF SAIDSHAPED RESILIENT INSERTS MOUNTED BENEATH SAID ELECTRICAL LEADS ANDEXTENDING ALONG THE BOTTOM OF SAID CHANNEL, (F) A SECOND RESILIENTPREFORMED INSERT MOUNTED ABOVE AND IN MATING CONTACT WITH SAIDELECTRICAL LEADS AND SAID PREFORMED INSERT TO THEREBY TOTALLYENCAPSULATE SAID ELECTRICAL LEADS AND SAID TERMINAL POST AND PREVENT THEPOSSIBILITY OF POSSIBLE HIGH VOLTAGE ARCING AND CORONA EFFECTS TOADJACENT OBJECTS, AND (G) A TOP PLATE SECURELY MOUNTED ON SAID TERMINALBODY AND IN CONTACT WITH SAID SECOND PREFORMED INSERT TO THEREBY ASSURETHE ELECTRICAL INTEGRITY OF SAID ELECTRICAL LEAD WIRES.